support redis sentinel config#added

[linhbkhn95]

Background Currently, Redis v8 doesn't support passing Redis sentinels via URL as I know from their code.

func ParseURL(redisURL string) (*Options, error) {
    u, err := url.Parse(redisURL)
    if err != nil {
        return nil, err
    }

    switch u.Scheme {
    case "redis", "rediss":
        return setupTCPConn(u)
    case "unix":
        return setupUnixConn(u)
    default:
        return nil, fmt.Errorf("redis: invalid URL scheme: %s", u.Scheme)
    }
}

So, As the author @hibiken mentioned in https://github.com/hibiken/asynqmon/issues/235 will not perform for Redis sentinels, terminal will show an error as Redis v8 defined redis: invalid URL scheme redis+sentinel

Why did we need it?

• Support pass Redis sentinel config via passing redis-master-name and redis-addrs to flag or REDIS_MASTER_NAME and REDIS_ADDS to environment
• Refactor flag that we will flag redis-addrs to detect users who want to use Redis standalone or clusters when do not pass redis-master-name, otherwise it will be redis sentinels. So we can deprecate redis-addr and redis-cluster-nodes flag

fixed https://github.com/hibiken/asynqmon/issues/235

[hibiken]

@linhbkhn95 Thanks for the PR! I've already started working on a fix and I just created a PR with that branch #241 (sorry for not communicating sooner 🙏 )

Reason for closing this PR:

• We'd like to avoid deprecating these flags and want to keep supporting them (at least for now).